未分化型癌・組織混合型癌

Factor Associated with Incorrect Diagnosis of Margins in Undifferentiated Type Early Gastric Cancer：Clinical Approach for Difficult Cases

要旨●早期胃癌のうち，未分化型癌の範囲診断誤診に寄与する因子について検討した．2002年9月〜2017年12月の間に，術前に未分化型癌と診断されESDが行われた282例を対象とした．ESD施行時のマーキング内に病変が限局している症例を範囲診断正診例と定義し，範囲診断誤診に寄与する因子について比較検討した．ESDのマーキング外進展例は29病変（10.3%）にみられ，ESDのマーキング外進展に寄与する因子として，M領域の病変，M-NBI使用なし，最終陰性生検陽性が抽出された．本検討の結果から，未分化型癌の範囲診断困難例に対しては，ESD前にM-NBIを用いて周囲陰性生検を行い，陰性生検陰性を確認することが重要と考える．

　We aimed to investigate the factors associated with incorrect diagnosis of margins in UD-EGC（undifferentiated type early gastric cancer）. We analyzed 282 lesions preoperatively diagnosed as UD-EGC that had undergone ESD（endoscopic submucosal dissection）between September 2002 and December 2017. We defined lesions with correct diagnosis of margin as the dissected lesion within the markings placed before ESD. We defined “negative biopsies” as biopsy samples taken from non-cancerous tissues around the lesion to determine resection margins before ESD. Logistic regression analysis was performed to identify preoperative factors related to incorrect diagnosis of margin. There were 29 lesions（10.3%）with an incorrect diagnosis of margin. Multivariate analysis revealed lesions located in the middle third of stomach, no use of NBI（narrow band imaging）, and positive result for malignancy in negative biopsies to be significant factors associated with incorrect diagnosis of margin. We should use NBI and confirm negative result for malignancy in negative biopsies before conducting ESD for UD-EGC.